The present disclosure is related to an apparatus for the measurement of performance characteristics of a nozzle for spraying fluids. More specifically, the present disclosure is related to an apparatus and method for measuring spray angle, spray uniformity, and spray velocity using laser sheet tomography.
Measurement of spray angles and spray uniformity are important in numerous applications in a wide variety of industries. The automotive industry is concerned with fuel pattern uniformity and spray angles from fuel injectors to control combustion in internal combustion engines. The coating industry is interested in nozzle characterization to assure proper coating thickness and uniformity of appearance. In painting applications, the spray inclination and angle determines transfer efficiency. In pharmaceutical applications, spray inclination affects the particle deposition in airways. In agricultural sprayers, spray angle and boom height are critical to providing uniform spray coverage.
Spray angles have been measured mechanically with collection cups or with special paper, but such approaches are subject to operator interpretation. It has been shown that operator interpretation may vary by as much 20% with the same operator. Optical methods have been developed using scattered light from a laser or backlit imaging. In addition, laser induced fluorescence and holography have been used. Such approaches are limited to measuring surface area density of drops of spray material or mass concentrations. Dense sprays limit the usefulness of the optical approaches and dynamic flux information is not available. This is due to the scattering of light when the backlit approach is used.
U.S. Pat. No. 6,184,989 discloses an apparatus and control system for obtaining flow field statistics in non-steady and steady state flows using laser sheet tomography. A collimated laser sheet is formed by a laser illuminator and a flow field is passed through the sheet. An imaging system either detects the light scattered from the laser sheet by the flow field when the imaging system is positioned orthogonally to the laser illuminator, or the laser illuminator is directed to the imaging system with the imaging system detecting the extinction image to determine the flow field characteristics.